"""OpenAPI Specification and Schema Invariants Contract Test Suite.

Validates the full OpenAPI 3.x schema generated by FastAPI, ensuring:
1. Complete path registration across all routers.
2. Valid operation IDs, methods, and tags.
3. Response schemas and JSON content-type definitions.
4. Schema integrity in components (no broken $ref pointers).
"""

from __future__ import annotations

import pytest

from app.main import app


@pytest.fixture(scope="module")
def openapi_schema() -> dict:
    """Generate OpenAPI specification dictionary from FastAPI app."""
    schema = app.openapi()
    assert isinstance(schema, dict), "OpenAPI schema must be a dictionary"
    return schema


def test_openapi_core_structure(openapi_schema: dict):
    """Validate core OpenAPI document properties."""
    assert "openapi" in openapi_schema
    assert openapi_schema["openapi"].startswith("3.")
    assert "info" in openapi_schema
    assert "title" in openapi_schema["info"]
    assert "version" in openapi_schema["info"]
    assert "paths" in openapi_schema
    assert len(openapi_schema["paths"]) >= 25, "At least 25 core API paths must be registered"


def test_openapi_required_routes_presence(openapi_schema: dict):
    """Verify that all essential platform routes are present in OpenAPI schema."""
    paths = openapi_schema["paths"]

    expected_critical_endpoints = [
        "/api/v1/simulations",
        "/api/v1/simulations/{simulation_id}",
        "/api/v1/simulations/{simulation_id}/ai-act-report",
        "/api/v1/banks",
        "/api/v1/banks/distributions",
        "/api/v1/training/{simulation_id}/rounds",
        "/api/v1/alerts",
        "/api/v1/alerts/{alert_id}",
        "/api/v1/alerts/{alert_id}/explain",
        "/api/v1/alerts/{alert_id}/counterfactuals",
        "/api/v1/alerts/{alert_id}/decision-replay",
        "/api/v1/alerts/{alert_id}/gnn-explanation",
        "/api/v1/cases",
        "/api/v1/cases/{case_id}",
        "/api/v1/cases/{case_id}/evidence",
        "/api/v1/cases/audit/logs",
        "/api/v1/entities",
        "/api/v1/graph/{entity_id}",
        "/api/v1/graph/stats/summary",
        "/api/v1/entities/psi",
        "/api/v1/entities/fuzzy-resolve",
        "/api/v1/rules",
        "/api/v1/rules/test",
        "/api/v1/security/status",
        "/api/v1/security/abac/evaluate",
        "/api/v1/security/audit-chain",
        "/api/v1/security/audit-chain/verify",
        "/api/v1/monitoring/drift/analyze",
        "/api/v1/monitoring/calibration",
        "/api/v1/monitoring/alerts",
        "/api/v1/coordinator/clients",
        "/api/v1/coordinator/negotiate",
        "/api/v1/privacy-defense/aggregation-methods",
        "/api/v1/privacy-defense/budget-log",
        "/api/v1/privacy-defense/audit/mia",
        "/api/v1/privacy-defense/audit/model-inversion",
        "/api/v1/registry/{simulation_id}/versions",
        "/api/v1/registry/{simulation_id}/shadow/metrics",
        "/api/v1/scenarios",
        "/health",
    ]

    for endpoint in expected_critical_endpoints:
        assert endpoint in paths, f"Missing critical endpoint in OpenAPI spec: {endpoint}"


def test_openapi_operation_contracts(openapi_schema: dict):
    """Validate HTTP methods, status codes, and response structures for all operations."""
    paths = openapi_schema["paths"]

    for path_str, methods in paths.items():
        for method_name, operation in methods.items():
            if method_name.startswith("x-") or method_name == "parameters":
                continue

            assert isinstance(operation, dict), f"Operation {method_name} {path_str} must be a dict"
            assert "responses" in operation, f"Operation {method_name} {path_str} must declare responses"

            # Verify status code contracts
            responses = operation["responses"]
            has_success_code = any(
                code.startswith("2") or code == "default" for code in responses
            )
            assert has_success_code, f"Operation {method_name} {path_str} missing 2xx success response"


def test_openapi_component_schema_integrity(openapi_schema: dict):
    """Verify that all schemas in components have valid property definitions and resolvable refs."""
    components = openapi_schema.get("components", {})
    schemas = components.get("schemas", {})
    assert len(schemas) > 0, "OpenAPI components must contain model schemas"

    for schema_name, schema_obj in schemas.items():
        assert isinstance(schema_obj, dict), f"Schema {schema_name} must be a dictionary"
        # Verify that schema defines title or type
        assert "type" in schema_obj or "properties" in schema_obj or "enum" in schema_obj or "allOf" in schema_obj or "anyOf" in schema_obj, (
            f"Schema {schema_name} must have a valid structural descriptor"
        )